I can't agree more with you. That's the one and only reason I'll stick to the 1.11 version.

Garanty of compatibility between Django and ALL my external packages is a lot more valuable that a responsive admin panel and a new syntax for urls.

I would love "important" (yeah it's opiniated) packages move to the official Django repo (like Channels), to help reduce this risk when migrating. It's actually surprising how often I can't find the compatibility information of a Django package.